We are attempting to understand the intracellular pathways which regulate the growth and migration of vascular smooth muscle cells (smc). This is of particular interest since smooth muscle cell proliferation and migration is thought to be largely responsible to restenosis following balloon angioplasty, as well as being an initial event in atherosclerosis. Using techniques of molecular and cell biology, we are attempting to understand how extracellular (outside) signals are converted into pathways inside the cell that stimulate proliferation and movement. We have concentrated on how tyrosine phosphorylation is regulated in vascular smooth muscle cells and how that process is controlled by ras proteins and how it may be modulated by reactive oxygen intermediates (ROI).